# std::ranges::common_view<V>::end

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< cpp‎ | ranges‎ | common view

constexpr auto end() requires (!/*simple-view*/<V>); | (1) | (since C++20)
constexpr auto end() const requires ranges::range<const V>; | (2) | (since C++20)

1) Returns an iterator representing the end of the `common_view`, that is:

- ranges::begin(base_) + ranges::distance(base_), if both ranges::random_access_range<V> and ranges::sized_range<V> are satisfied,
- std::common_iterator<ranges::iterator_t<V>, ranges::sentinel_t<V>>(ranges::end(base_)) otherwise.

Here `base_` (the name is for exposition purposes only) is the underlying view.
2) Same as (1), but `V` is const-qualified.

### Parameters

(none)

### Return value

An iterator representing the end of the underlying view.

### Example

Run this code

    #include <iostream>
    #include <numeric>
    #include <ranges>

    int main()
    {
        constexpr int n{4};

        constexpr auto v1 = std::views::iota(1)
                          | std::views::take(n)
                          | std::views::common
                          ;
        constexpr auto v2 = std::views::iota(2)
                          | std::views::take(n)
                          ;
        const int product = std::inner_product(v1.begin(), v1.end(),
                                               v2.begin(),
                                               0);
        std::cout << product << '\n';
    }

Output:

    40

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 4012 | C++20 | non-const overload missed simple-view check | added

### See also

begin | returns an iterator to the beginning (public member function)
ranges::begin (C++20) | returns an iterator to the beginning of a range (customization point object)
ranges::end (C++20) | returns a sentinel indicating the end of a range (customization point object)

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